Sodium salts, soluble

C12H12N2O3. White crystals, m.p. 174°C. Prepared by condensing the ethyl ester of phenylethylmalonic acid with urea. It is a more active hypnotic than barbitone. It and its sodium salt - soluble phenobarbitone - are used as sedatives and in treating epilepsy. 

Rohm and Haas introduced recently two new members of the diphenyl ether group, namely 5-(2-chloro-4-trifluoromethyl)phenoxy-2-nitrobenzoic acid (acifluorfen, 4) and 2-chloro-4-(trifluoromethyl)phenyl 3-ethoxy-4-nitrophenyl ether (oxyfluorfen, 5) (Biroli et al., 1980 Theissen, 1982 Swithenbank, 1982). Acifluorfen is used as its sodium salt soluble in water. 

Synonyms Silicic acid, sodium salt Soluble glass Water glass Definition Sodium salt of silicic acid Empirical NaeOjSij NajOjSi,... 

Synonyms Silicic acid, sodium salt Soluble glass Water glass... 

NHCOCH3. White crystals, m.p. 18l-l83"C. Soluble sulphacetamide is the sodium salt which is soluble in water. Il is prepared by acetylating sulphanilamide and hydrolysing one acetyl group. Being more soluble than most of the sulphonamides it is used in treating infections of the urinary tract and of the conjunctiva. 

C10H10N4O2S. White powder, which darkens on exposure to light m.p. 255-256 C. Prepared by condensing p-acet-amidobenzenesulphonyl chloride with 2-aminopyrimidine and subsequent hydrolysis. Soluble sulphadiazine is the sodium salt. Sulphadiazine is the least toxic of the more potent sulphonamides. ... 

Although the data for the silver halides suggest that silver(I) fluoride is likely to be more soluble than the other silver halides (which is in fact the case), the hydration enthalpies for the sodium halides almost exactly balance the lattice energies. What then is the driving force which makes these salts soluble, and which indeed must be responsible for the solution process where this is endothermic We have seen on p. 66 the relationship AG = — TAS and... 

On the addition of sodium hydroxide, the sparingly soluble sodium salt of methyl-orange, NaOsSCeHgN .NCgHgNfCHj), will crystallise out. 

Arylarsonic acids have usually a very low solubility in cold water. They are however amphoteric, since with, for example, sodium hydroxide they form sodium salts as above and with acids such as hydrochloric acid they form salts of the type [CaHjAsCOHljlCl. Both types of salt are usually soluble in water, and to isolate the free acid the aqueous solution has to be brought to the correct pH for most arsonic acids this can be achieved by niaking the solution only just acid to Congo Red, when the free acid will usually rapidly separate. 

J Some sodium salts (particularly sodium oxalate) may be precipitated, due to their low solubility in NaOH solution. The salt should be redissolved by the addition of water before the subsequent distillatfon. 

Dilute sodium hydroxide solution (and also sodium carbonate solution and sodium bicarbonate solution) can be employed for the removal of an organic acid from its solution in an organic solvent, or for the removal of acidic impurities present in a water-insoluble solid or liquid. The extraction is based upon the fact that the sodium salt of the acid is soluble in water or in dilute alkali, but is insoluble in the organic solvent. Similarly, a sparingly soluble phenol, e.g., p-naphthol, CioH,.OH, may be removed from its solution in an organic solvent by treatment with sodium hydroxide solution. 

The normal form A can pass by tautomeric change under the influence of alkali into the acidic hydroxy form B, which in turn can 3deld the sodium salt C. Nitroparaffins are therrfore pseudo-acids, and are soluble in alkaline solution. 

It is frequently advisable in the routine examination of an ester, and before any derivatives are considered, to determine the saponification equivalent of the ester. In order to ensure that complete hydrolysis takes place in a comparatively short time, the quantitative saponi fication is conducted with a standardised alcoholic solution of caustic alkali—preferably potassium hydroxide since the potassium salts of organic acids are usuaUy more soluble than the sodium salts. A knowledge of the b.p. and the saponification equivalent of the unknown ester would provide the basis for a fairly accurate approximation of the size of the ester molecule. It must, however, be borne in mind that certain structures may effect the values of the equivalent thus aliphatic halo genated esters may consume alkali because of hydrolysis of part of the halogen during the determination, nitro esters may be reduced by the alkaline hydrolysis medium, etc. 

Aliphatic amides may be hydrolysed by boiling with 10 per cent, sodium hydroxide solution to the corresponding acid (as the sodium salt) the alkahne solution should be acidified with dilute sulphuric acid any water-soluble acid may then be distilled from the solution. Alternatively, hydrolysis may be eflfected with 10-20 per cent, sulphuric acid. The resulting ahphatic acid (usually a liquid) may be characterised as detailed in Section 111,85. 

With phenylalanine and tyrosine, the sodium salt of the derivative is sparingly soluble in water and separates during the initial reaction. Acidify the suspension to Congo red the salts pass into solution and the mixture separates into two layers. The derivative is in the etheresil lay and crystallises from it within a few minutes. It is filtered off and recrystaUised. 

Because of the great solubility of sulphonic acids in water and the consequent difficulty in crystallisation, the free sulphonic adds are not usually isolated but are converted directly into the sodium salts. The simplest procedure is partly to neutralise the reaction mixture (say, with solid sodium bicarbonate) and then to pour it into water and add excess of sodium chloride. An equilibrium is set up, for example ... 

The high sodium ion concentration results in facile crystallisation of the sodium salt. This process of salting out with common salt may be used for recrystallisation, but sodium benzenesulphonate (and salts of other acids of comparable molecular weight) is so very soluble in water that the solution must be almost saturated with sodium chloride and consequently the product is likely to be contaminated with it. In such a case a pure product may be obtained by crystallisation from, or Soxhlet extraction with, absolute alcohol the sul-phonate is slightly soluble but the inorganic salts are almost insoluble. Very small amounts of sulphones are formed as by-products, but since these are insoluble in water, they separate when the reaction mixture is poured into water ... 

The sodium salt of methyl red may be prepared by dissolving the crude product in an equal weight of 35 per cent, sodium hydroxide which has been diluted to 350 ml., hitoring, and evaporating under diminished pressure (Fig. II, 37, I). The resulting sodium salt forms orange leaflets. This water-soluble product is very convenient for use as an indicator. Incidentally, the toluene extraction is avoided. 

The solution will then contain the free acid and the hydrochloride of the base either of these may separate if sparingly soluble. If a sohd crystallises from the cold solution, filter, test with sodium bicarbonate solution compare Section 111,85, (i) and compare the m.p. with that of the original compound. If it is a hydrolysis product, examine it separately. Otherwise, render the filtrate alkahne with sodium hydroxide solution and extract the base with ether if the presence of the unchanged acyl canpound is suspected, extract the base with weak acid. Identify the base in the usual manner (see Section IV, 100). The acid will be present as the sodium salt in the alkaline extract and may be identified as described in Section IV,175. 

Saccharin Itself is sparingly soluble in cold water, but the imino hydrogen is acidic and the compound forms a water-soluble sodium salt. The latter is about 600 times as sweet as cane sugar. 

With sodium hydroxide as the base boron of the alkylborane is converted to the water soluble and easily removed sodium salt of boric acid... 

The solubility behavior of salts of carboxylic acids having 12—18 carbons is unusual and can be illustrated by considering sodium stearate (sodium octadecanoate) As seen by the structural formula of its sodium salt... 

Two inorganic water-soluble polymers, both polyelectrolytes in their sodium salt forms, have been known for some time poly(phosphoric acid) (12) and poly(siHcic acid) (13). A more exciting inorganic water-soluble polymer with nonionic... 

Potassium acetate, mbidium acetate, and cesium acetate are very soluble ia anhydride ia contrast to the only slightly soluble sodium salt. Barium forms the only soluble alkaline earth acetate. Heavy metal acetates are poorly soluble. 

The metallic salts of trifluoromethanesulfonic acid can be prepared by reaction of the acid with the corresponding hydroxide or carbonate or by reaction of sulfonyl fluoride with the corresponding hydroxide. The salts are hydroscopic but can be dehydrated at 100°C under vacuum. The sodium salt has a melting point of 248°C and decomposes at 425°C. The lithium salt of trifluoromethanesulfonic acid [33454-82-9] CF SO Li, commonly called lithium triflate, is used as a battery electrolyte in primary lithium batteries because solutions of it exhibit high electrical conductivity, and because of the compound s low toxicity and excellent chemical stabiUty. It melts at 423°C and decomposes at 430°C. It is quite soluble in polar organic solvents and water. Table 2 shows the electrical conductivities of lithium triflate in comparison with other lithium electrolytes which are much more toxic (24). 

Carboxymethylcellulose Sodium. Carboxymethyl ether of cellulose sodium salt (Citmcel) (8) is a white granular substance soluble in water depending on the degree of substitution. It is equally soluble in cold and hot water and may be prepared by treating alkaU cellulose with sodium chloroacetate. 

Docusate Sodium. Aerosol OT, Colace, and Doxinate are trade names of docusate sodium [577-11-7] (dioctyl sodium sulfo succinate, sodium salt of l,4-bis(2-etliylhexyl)estet butanedioic). This white, wax-like, plastic sohd, with a characteristic odor suggestive of octyl alcohol, is usually available in the form of pellets. One gram of the sodium salt slowly dissolves in about 70 mL water. Docusate sodium is freely soluble in alcohol and glycerol, very... 

---